JP3219376B2 - Low emittance electron storage ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron storage ring for use in a synchrotron radiation device, and more particularly, to obtaining a high-brightness synchrotron radiation by inserting a superconducting wiggler, a multipolar superconducting wiggler, a mini-undulator, etc. To an electron storage ring.

[0002]

2. Description of the Related Art A recent electron storage ring for a synchrotron radiation generator has a double-bend chromatic cell (DBA) or DBA composed of two bending electromagnets and a plurality of quadrupole electromagnets sandwiched therebetween. In general, a lattice is formed using a triple bent chromatic cell (TBA) configured by incorporating another bending electromagnet into the lattice. In these electron storage rings using DBA or TBA, the dispersion function at both ends of the cell is set to zero, and an insertion light source is disposed at an intermediate position between the cells.

On the other hand, in order to obtain high-luminance radiated light from the radiated light ring, it is essential to reduce the emittance, and it is preferable that the emittance be 10 nm-rad or less. However, when trying to make the dispersion function zero at both ends of the DBA or TBA, it becomes difficult to minimize the emittance, for example, several nm-r under a predetermined electron energy.
In order to obtain the horizontal emittance of ad, an electron storage ring having a large circumference and a large cost using an enormous number of cells results.

The horizontal beam emittance ε _x in an electron storage ring formed by using a bending electromagnet having the same deflection radius ρ is represented by γ is a Lorentz factor representing the energy of electrons, and J _x is a damping partition numbe.
When r) and H are lattice invariants, they are expressed by the following equation. However, <> means an average value over the entire circumference of the electron storage ring. ε _x = C _q γ ² <H> / (J _x ρ) (1) H = γ _x η ² + 2α _x ηη ′ + β _x η ′ ² (2) where C _q is a constant, 3.84 × 10 ⁻¹³ m, η is a horizontal dispersion function, η ′ is its slope, and α _x , β _x , and γ _x are lattice functions known as Twiss parameters.

Accordingly, in order to reduce the emittance ε, it is necessary to reduce <H> or reduce the lattice function in the corresponding bending electromagnet. However, in this case, the value of β _{x in} the quadrupole electromagnet adjacent to the end of the bending electromagnet may be unacceptably large. Further, in order to further reduce the influence of the superconducting wiggler on the beam dynamics, it is required that the dispersion in the linear portion where the wiggler is inserted is reduced to zero. Otherwise, the strong field of the wiggler would significantly increase the beam emittance and limit the performance of the device. Therefore, usually, in order to make the dispersion in the linear portion where the superconducting wiggler is set to zero, a light source configuration in which a large number of achromatic bends are arranged is used.

[0006] In order to minimize the emittance and to form a linear portion without dispersion as described above, as a conventionally used one, Chasmann-Green has been used.
Double Bend Achromatic Cell (CG) and Triple Bend Achromatic Cell (TBA). CG
Basically consists of two 2-pole magnets and a large number of 4-pole magnets sandwiched between them.
It has a structure with pole magnets.

The calculation for properly selecting the lattice function in the bending magnet is easy, and the minimum emittance for CG and TBA is given by the following equation. ε _x = C _m γ ² θ ³ (3) where θ = 2π / N _c is an achromatic angle,
N _c is the number of cells, and C _m is a constant specific to the lattice. The emittance is proportional to the square of the beam energy, and the deflection angle is 3
This relation of proportionality to the power is not specific to CG and TBA, but is a general property.

As can be seen from the above, in order to reduce the emittance ε under a certain amount of energy γ, it is necessary to increase the lattice cell number N _c and decrease θ. This has the consequence of increasing the perimeter of the device and increasing costs. Another method of reducing the emittance is to use a lattice of new formats constant C _m is smaller than that of CG or TBA.

[0009]

The problem to be solved by the present invention is to construct a small electron storage ring with low emittance by using a new type of compact lattice.

[0010]

In order to solve the above-mentioned problems, an electron storage ring according to the present invention comprises three series-type bending electromagnets arranged in series and two bending electromagnets interposed between the bending electromagnets. The basic quadrupole electromagnet is constituted as a main element, and the quadrupole electromagnet is selected so as to minimize the horizontal beta function and the dispersion function at the center of the bending electromagnet even if the dispersion function at the end of the module becomes relatively large. The emittance is optimized by forming a lattice using the triple chromatic bend (TCB) as a first basic module.

Further, two quadrupole electromagnets for correction are further provided at both ends of the first basic module.
The vertical beta function at the module end is 0.3-0.7 m and the horizontal beta function is 10-18
m, and the insertion light source is disposed here with the gap between the first basic modules as a linear portion. Note that the insertion light source inserted into the linear portion may be a mini-undulator.

Further, the electron storage ring according to the present invention comprises:
In addition to the above-mentioned first basic module, two first bending electromagnets, two second bending electromagnets having half the length of the first bending electromagnet, and two quadrupole electromagnets are main components. A first bending electromagnet, a four-pole electromagnet, a second bending electromagnet, a second bending electromagnet, a four-pole electromagnet, and a first bending electromagnet. A lattice may be formed including a second basic module in which the dispersion function in the linear portion is reduced by a quadrupole electromagnet.

It is preferable that the second basic module further includes a quadrupole electromagnet for correction so that the beta function of the linear portion is stabilized by the quadrupole electromagnet for correction. Further, the insertion light source inserted into the linear portion formed between the second deflection magnets of the second basic module may be a multipolar superconducting wiggler. Further, it is preferable that the first basic module and the second basic module are alternately arranged to incorporate a total of eight basic modules to form an electron storage ring.

Since the electron storage ring of the present invention uses triple chromatic bend (TCB), emittance can be minimized more easily, lower emittance can be realized at the same energy level, and a smaller and less expensive ring can be used. It is possible to configure. In the electron storage ring of the present invention, the horizontal beta function and the dispersion function are minimized at the center position of the bending electromagnet, so that a superconducting electromagnet capable of generating a strong magnetic field can be used as the bending electromagnet. Therefore, hard X-rays can be generated without affecting beam dynamics.

By providing two quadrupole electromagnets at the end of the TCB and adjusting the vertical beta function to be small,
It becomes possible to install a mini-undulator having a small gap in the straight section between the TCBs. Since the vertical emittance function in this straight portion is small, the beam life is long even for the gap of about 1.5 mm to 2 mm of the mini-undulator. If the central bending electromagnet is configured to have a length half that of the other bending electromagnets, one dimension adjustment is performed using a normal quadrupole electromagnet, so that a straight portion formed in the middle of the half length central bending electromagnet is formed. Since the dispersion function can be reduced to a small value and the differential value can be easily reduced to zero, a superconducting insertion light source, an RF cavity, and other accelerator equipment can be installed in this linear portion.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnet structure using a superconducting wiggler and a mini-undulator according to the present invention will be described in detail based on embodiments. The present inventors have newly constructed an electron storage ring using triple chromatic bend (TCB). The TCB is a compact cell having three dipole electromagnets and two quadrupole electromagnets as a basic configuration. The TCB is configured so as to satisfy the condition for minimizing the emittance without being particular about making the dispersion function at the end of the cell zero. Further, two pairs of quadrupole electromagnets are arranged between the basic cells, thereby adjusting the betatron envelope function so as to conform to the mini-undulator.

In the TCB, in order to approach the ideal optimum emittance as much as possible, β _{x is set} at the center of the bending electromagnet.
It was found that it was necessary to make several cm and η _x several cm. In the electron storage ring of the present invention using TCB as a basic component module, the constant C _m of the above equation (3) is 82
0 nm, which is extremely small as compared with a value of about 2600 nm (US: ALS) in the conventional electron storage ring.

The mini-undulator is a conventional undulator which is formed by providing a vacuum chamber through which an electron beam passes between rows of permanent magnets, so that the gap between the rows of magnets becomes about 2 cm to 3 cm and a strong magnetic field. Was difficult to apply, but the permanent magnet array was housed in a vacuum vessel to reduce the gap between the magnet arrays from 1.5 mm to 3 mm. In addition to forming a strong magnetic field to improve the intensity of the emitted light, the period length of the magnetic field can be shortened, and the wavelength of the emitted light can be shortened.

In order to determine an appropriate configuration for a particular lattice, it is necessary to carefully determine the value of the lattice function in the linear portion. In order to use the mini-undulator inserted into the electron storage ring, the width of the electron beam in the gap direction must be made sufficiently small to prevent the loss of high-speed electrons by contacting the gap side wall of the undulator, thereby ensuring the life of the electron beam. Must. It must be taken into account that the mini-undulator has a very narrow vertical aperture, so that the beam lifetime strongly depends on the value of β _z .

The process most involved in limiting the electron beam lifetime in a mini-undulator with a narrow gap is elastic scattering due to residual gas atoms called Rutherford scattering. This scattering results in an angular kick for betatron motion and particle loss when the increased amplification exceeds the aperture limit. The cross section of Rutherford scattering is given by: σ _s = 4pr _e ² Z (Z + 1) β _z0 <β _z > / (γ ² _az ² ) (4) where p is the pressure of the residual gas, Z is the number of atoms, and _az is half of the gap of the undulator. The aperture limit, β _z0, is the vertical envelope function at the undulator end. It can be seen that the scattering cross section strongly depends on the number of atoms Z. Actually, in the worst case where Z is the largest, Z becomes 7 with the nitrogen molecule N ₂ .

The elastic scattering lifetime τ _s is obtained by calculating the electron energy E by G
When eV and the pressure p of the residual gas are represented by nTorr, the following expression is obtained. τ _s = 10 ⁷ (E ² / p) ( _az ² / β _z0 <β _z >) (5) It should be noted here that β _z0 is not the envelope function β _zc at the center of the mini-undulator. , The maximum value of the vertical beta function in the undulator, that is, the value at the end point of the undulator. The following equation holds between the two. β _z0 = β _zc + L ² / 4β _zc (6) where L is the length of the undulator.

Thus, the maximum value β _z0 of the vertical beta function
Since the has a component that increases in proportion to the square of the length of the undulator and decreases in inverse proportion to the vertical beta function β _zc at the center, the beta function at the center of the mini-undulator straight section must not be reduced to a dark cloud You can see that. This is because if the vertical beta function β _z at the center of the undulator straight portion is reduced, the value β _z0 at the end of the undulator reaches an unacceptable level. Also, as shown in equation (5), the elastic scattering lifetime is inversely proportional to the product of the vertical beta function in the undulator and the average value of the vertical beta function over the entire ring. Therefore, in order to make the vertical beta function in the ring an appropriate value, the vertical beta function of the linear portion cannot be made too small.

A suitable linear beta function value under which a suitable ring vertical beta function value and scattering lifetime can be obtained under certain conditions is 0.5 m to 0.8 m. Under these conditions, it is known that when the linear part beta function becomes 0.4 m, the life which was 10 hours at 0.8 m becomes shorter by 4 hours. Selecting an appropriate vertical beta function in the storage ring and in the straight portion in this manner is also effective in reducing the vertical chromaticity.

On the other hand, the value of the horizontal beta function β _x in the mini-undulator is selected so as to minimize the size of the emitted light beam spot on the emission line of the emitted light beam. The beam size d _{x at a} distance L from the radiation position can be evaluated by the following equation. d _x ² = σ _x ² + L ² (σ _x ' ² + σ _r ' ² ) (7) Here, the beam size d _x is the half value of the beam cross section, σ _x is the spot size of the electron beam, σ _x ′ Represents the angular spread of the electron beam, σ _r ′ represents the spread inherent in the emitted light, and the beam size σ _r of the emitted light can be ignored with respect to the electron beam size σ _x . For example, when the width d _x of the emitted light when the distance L from the mini-undulator is 15 m is plotted against the horizontal beta function β _{x at} the center of the linear portion, the value of the horizontal beta function β _x is 16 m It can be seen that the value has a gradual minimum value during the change to 22 m, and the smaller the value, the larger the width d _{x of the} emitted light.

The brightness B of the light emitted from the mini-undulator can be expressed by the following equation. B = (photons _{^{flux) / (4π 2 Σ x Σ}} x 'Σ z Σ z') (8) where the position sigma _x of the ^{_{radiation, z 2 = σ x, z}} 2, and radiation angle spread sigma ^{_{x, z '2 = σ x}} , z 2 + σ r' is ^2. When plotting the value of the denominator of the equation (8) against the horizontal beta function β _{x at} the center of the straight line portion in the same manner as above, the minimum value of the horizontal beta function β _x is between 18 m and 22 m. It can be seen that the emission light luminance under this condition has a high value, and the emission light luminance decreases even when the beta function becomes smaller than this. As described above, the triple chromatic bend (TCB) is configured so that the horizontal beta function in the linear portion where the insertion light source such as the mini-undulator is inserted is within an appropriate range, and the luminance of the radiation light emitted from the insertion light source is set. Can be improved.

On the other hand, since the magnetic field of the superconducting wiggler has a large effect on the electron beam, it is important to properly select the lattice function value in the straight line portion where the wiggler is inserted. In order not to increase the beam emittance, the horizontal dispersion function in the superconducting wiggler must be zero. When the dispersion is zero or extremely small, the beam emittance can be reduced by wiggler.

The magnetic field generated by the superconducting electromagnet of the superconducting wiggler causes edge focusing in the vertical plane to have the effect of waving the vertical tune shift Δν _z and the beta function β _z around the ring according to the following equation. Have. Δν _z ≒ ave (β _z ) / 4π · <B _z ² / Bρ ² > · L (9) Δβ _z / β _z ≒ 2πΔν _z / sin (2πν _z ) (10) where L is the total length of the wiggler, ave (β _z ) is the average value of the vertical envelope function at the wiggler position, B _z is the magnetic field that traverses the wiggler, and Bρ is E (Ge
V) = 0.3Bρ (T · m) is the product of the magnetic field strength and the radius of curvature in the storage ring. <> Means an average value in the wiggler.

Therefore, in order to reduce the influence on the lattice, the wiggler is usually set at a position where the vertical beta function β _z is small, but it is still necessary to apply an appropriate correction. Experimentally, it has been found that it is convenient to make the vertical beta function β _z in the superconducting wiggler smaller than 6 m.

When angiography is performed using a superconducting wiggler, it is desirable that the size σ _{x of the} beam source be set to about 0.2 mm to 0.3 mm in order to improve spatial resolution. For this reason, the horizontal beta function β _x in the linear portion where the wiggler is inserted is restricted according to the following equation. β _x = σ _x ² / ε _x (11) where ε _x is the horizontal emittance. It has been found that in the electron storage ring under the above conditions, β _x is preferably 11 m or less.

By connecting the required number of basic modules thus configured in series to form an electron storage ring, and installing a necessary insertion light source or the like in the linear portion, a ring smaller than the storage ring according to the prior art can be obtained. Thus, it is possible to obtain a sufficiently high-intensity radiation. Further, a sufficiently long beam life can be ensured even if a mini-undulator, which was conventionally difficult to install, is inserted.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electron beam energy of 2.2 GeV,
The electron storage ring structure according to the present invention will be described in detail with reference to the drawings showing an embodiment that satisfies the specifications that the storage current is 0.3 A and the life of the electron beam is 10 hours or more. FIG.
FIG. 2 is an electromagnet arrangement diagram showing a basic module configuration used for the electron storage ring of the present invention, FIG. 2 is a diagram showing a lattice function in the electromagnet arrangement of FIG. 1, and FIG. Electromagnet layout diagram showing the configuration,
FIG. 4 is a diagram showing a lattice function in a quarter of a ring in which two sets of the electromagnet arrangement of FIG. 3 are connected. FIG. 5 is a drawing showing the arrangement of the electromagnets of the electron storage ring in this embodiment.

The basic module in the electron storage ring of this embodiment is the triple chromatic bend (TCB) shown in FIG. The TCB has a mirror-symmetric structure in which the main elements are composed of three bending electromagnets BM and two quadrupole electromagnets Q3. In FIG. 1, reference numerals 1, 2, and 3 denote bending electromagnets (BMs) having the same cross-sectional structure and magnetic field strength, and deflect an electron beam passing therethrough in a horizontal direction by a predetermined angle, 15 degrees in this embodiment. Quadrupole electromagnets (Q3) 4, 5 are arranged between the bending electromagnets. The two quadrupole electromagnets 4, 5 are used to appropriately adjust the lattice function in the bending electromagnet by converging the electron beam to generate a smaller horizontal emittance.

FIG. 2 shows how the lattice function changes along the trajectory of the electron beam in the TCB. Lattice functions displayed in FIG. 2 is a horizontal beta function beta _x and the vertical beta function beta _z dispersion function eta. The dispersion function η represented by the solid line in the figure increases after taking the minimum value at the center of the first bending electromagnet 1, and then decreases again by the quadrupole electromagnet 4 to decrease the minimum value at the center of the middle bending electromagnet 2. Take. Thereafter, the increase is reduced by the second quadrupole electromagnet 5, and is increased by taking the minimum value at the center of the third bending electromagnet 3.

A pair of quadrupole electromagnets (Q1, Q2) 6, 7 for adjusting the beta function in the linear portion outside the basic module are arranged upstream of the first bending electromagnet 1, and furthermore, the electron beam A six-pole electromagnet (SF) 8 for convergence and a six-pole electromagnet (SD) 9 for diffusion are arranged to adjust the shape and reduce chromaticity. Downstream of the third bending electromagnet 3, the quadrupole electromagnets (Q2, Q2) are mirror-symmetrical to the quadrupole electromagnets 6, 7 and the hexapole electromagnets 8, 9.
1) 10, 11, and 6-pole electromagnets (SD, SF) 12,
13 is provided to recover the shape of the electron beam and supply it to the next module.

The horizontal beta function β _x represented by the dashed line in FIG. 2 is also adjusted so as to exhibit a change almost similar to the dispersion function η. The vertical beta function β _z represented by a broken line in the figure takes a minimum value of about 0.3 m to 0.7 m at the end of the TCB and increases at the positions of the bending electromagnets 1, 2, and 3. The position is adjusted so as to be as large as about 14 m at the positions of the electromagnets 1 and 3 and as small as about 3 m at the position of the central bending electromagnet 2.

The electron storage ring is configured in such a manner that eight basic modules are connected in series via straight portions. The linear portion has, for example, 2 m and a vertical beta function β _z of about 0.3 to 0.7 m. A beam position sensor, a steering magnet, a mini-undulator, and the like are installed here. Note that the horizontal beta function β
_{Since x} is as large as about 18 m, an electron injection device can be provided here.

Further, a straight portion for installing a superconducting device such as a superconducting wiggler is provided at a central portion of four second basic modules disposed every other one of the eight. FIG. 3 is an arrangement diagram showing an eighth portion of an electron storage ring formed by connecting half of the first basic module and half of the second basic module obtained by dividing the central bending electromagnet. The figure shows half of the first basic module on the left and half of the second basic module on the right. In the figure, the same elements as those in FIG. 1 are denoted by the same reference numerals. The magnet configurations of FIG. 3 are connected in plane symmetry to form one electron storage ring.

The second basic module is obtained by dividing the central bending electromagnet 2 of the first basic module described with reference to FIG. 1 into two electromagnets (DB) 21 having a half length and separating them from each other. Between the bending electromagnets 21 is a linear portion. The quadrupole electromagnet (Q31) 22 installed between the bending electromagnet 1 and the half-length bending electromagnet 21 has a position η _x and an angular spread η _x ′ of the horizontal dispersion function in the half-length bending electromagnet 21.
Has a function to make zero. The beta function in this linear part is represented by three quadrupole electromagnets (Q4, Q5, Q6) 23, 2
It is adjusted to an acceptable value by 4, 25, and it is not necessary to provide a special quadrupole electromagnet.

A straight section of about 2 m is formed between the first basic module drawn on the left part of FIG. 3 and the second basic module drawn on the right part, and this straight part is, for example, a mini-undulator as described above. 31 is inserted. A superconducting wiggler 32 is provided in a straight line portion half-displayed at the rightmost end in the drawing. The straight portion sandwiched between the half-length bending electromagnets has a length of about 3 m. As can be seen from FIG. 4, the dispersion function η in the linear portion is almost zero as described above, but the horizontal beta function β _x is about 10 m, and the vertical beta function β _z is about 4 m, which are moderate values. Has been adjusted as follows. An RF cavity can be provided in this straight section.

Table 1 shows an example of selection of a lattice function in this embodiment satisfying the above conditions. Table 2 shows an example of parameter selection for a bending electromagnet, and Table 3 shows an example of parameter selection for a quadrupole electromagnet.

[0041]

[Table 1]

[Table 2]

[Table 3]

FIG. 5 shows the entire electron storage ring of the present embodiment constituted by using four first basic modules and four second basic modules. The electron beam is generated by the linac 31 and reduced in size. Is accelerated by the synchrotron 42 and is incident on the electron storage ring 43 at a proper timing.
The electron storage ring 43 includes four first basic modules 44.
And four second basic modules 45 are alternately connected in series to form a ring, and a high-frequency accelerator 46 is provided to compensate for the energy of the beam lost by the emitted light during the ring. In the electron storage ring 43, the emitted light SR is emitted from the central bending electromagnet 51 of the first module.
A superconducting wiggler (SCS) 52 or a multi-pole superconducting wiggler MSW5 is provided in a straight portion provided at the center of the second basic module.
3 to generate radiated light, and another type of radiated light to be generated by installing an insertion light source such as a mini-undulator 54 in a linear portion formed between the first basic module and the second basic module. it can.

The electron storage ring of the present embodiment in which the TCB constructed as described above is formed as a basic module has a circumference of 120 m for a capacity of, for example, 2.2 GeV.
The size and the average diameter can be made extremely small, about 38 m, the production cost is low, and the emittance is small, so that high-intensity emitted light can be obtained for the small size. The specific dimensions and function values appearing in the description of the present embodiment are merely used for clarifying the description, and are required for the electron storage ring without departing from the technical idea of the present invention. Needless to say, it can be arbitrarily changed based on the specifications.

[0044]

As described above, the electron storage ring of the present invention can more easily achieve the minimization of emittance by using the triple chromatic bend (TCB) and obtain high-brightness radiation light with a small ring. it can. The electron storage ring of the present invention can use a superconducting electromagnet to generate hard X-rays without affecting beam dynamics. Even if a mini-undulator having a small gap is used, the beam life is long and long-term operation is possible.

[Brief description of the drawings]

FIG. 1 is an electromagnet arrangement diagram showing a basic cell configuration used for an electron storage ring according to the present invention.

FIG. 2 is a drawing showing a lattice function in the electromagnet arrangement of FIG.

FIG. 3 is an electromagnet arrangement diagram showing a basic configuration corresponding to one-eighth of an electron storage ring according to an embodiment of the present invention.

FIG. 4 is a quarter of an electron storage ring according to an embodiment of the present invention.
3 is a drawing showing a lattice function in a portion corresponding to FIG.

FIG. 5 is an arrangement diagram of electromagnets of an electron storage ring in the present embodiment.

[Explanation of symbols]

 1, 2, 3 bending electromagnet 4, 5 quadrupole electromagnet 6, 7, 10, 11 quadrupole electromagnet 8, 9, 12, 13 6 pole electromagnet 21 deflection electromagnet 22, 23, 24, 25 quadrupole electromagnet 31 undulator 32 superconductivity Wigler 41 Linac 42 Synchrotron 43 Electron storage ring 44 First basic cell 45 Second basic cell 46 RF cavity 51, 52, 53, 54 Light source

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-68995 (JP, A) JP-A-8-153598 (JP, A) JP-A-2-72600 (JP, A) JP-A-2- 27700 (JP, A) JP-A-62-32000 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H 13/04

Claims (8)

(57) [Claims] The main components are three electromagnets of the same type arranged in series and two quadrupole electromagnets interposed between the electromagnets, and the quadrupole electromagnet is connected to an end of the module. almost poles each horizontal beta function and the dispersion function at the center of the deflection electromagnet regardless dispersion function in
An electron storage ring in which emittance is optimized by assembling a lattice using a first basic module selected to have a small value.
However, two quadrupole electromagnets are provided at both ends for correction.
The four-pole electromagnet for correction hangs at the module end.
0.3 to 0.7 m for direct beta function and 1 for horizontal beta function
Adjusted to 0-18m, between the first basic modules
Characterized in that an insertion light source is arranged in the gap of
Storage ring . Wherein an electron storage ring according to claim 1, wherein the insertion device is a mini undulator. 3. A first deflection electromagnet having two first deflection electromagnets, two second deflection electromagnets having half the length of the first deflection electromagnets, and two quadrupole electromagnets as main elements. Bending magnet , quadrupole magnet , second bending electromagnet , second bending electromagnet , 4
A second configuration in which a pole electromagnet and a first deflection electromagnet are arranged in series in this order, and the dispersion function in the linear portion is reduced by the quadrupole electromagnet, with a linear portion between the second deflection electromagnets. 3. The electron storage ring according to claim 1, wherein a lattice is formed including a basic module. 4. A three-part, first type of first and second same type arranged in series.
Two first electromagnets and two first electromagnets
The first four-pole electromagnet is constituted as a main element,
Polar electromagnet depends on the dispersion function at the end of the module
Horizontal beta function and dispersion at the center of the bending magnet
Each of the functions is chosen to be a local minimum
And one of the basic module, and the second bending magnet two groups, and the third deflection electromagnet 2 groups having half the length of the second bending magnet, the main component of the second quadrupole electromagnets 2 group As
A second bending electromagnet, a second quadrupole electromagnet, a third bending electromagnet,
A third bending electromagnet, a second quadrupole electromagnet, and a second bending electromagnet are arranged in series in this order, and the linear section is formed by the second quadrupole electromagnet with the third bending electromagnet as a linear section. By forming a lattice including a second basic module adapted to reduce the dispersion function at
Electron storage ring optimized for 5. The second basic module further comprises a quadrupole electromagnet for correction, wherein the quadrature electromagnet for correction sets the dispersion function of the linear portion close to zero to stabilize the beta function. Item 5. An electron storage ring according to item 3 or 4. Wherein said second basic claim 3 which is disposed an insertion device in a linear portion formed between the second deflection magnet modules
6. The electron storage ring according to any one of claims 1 to 5 . 7. The electron storage ring according to claim 6, wherein said insertion light source is one of a superconducting wiggler and a multipolar superconducting wiggler. 8. The electron storage ring according to claim 3, wherein the first basic modules and the second basic modules are alternately arranged to incorporate eight basic modules.